variadic function call broken on armhf when passing a float argument

GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2020-02-14.10:03:28.170>
labels = ['3.8', '3.9', '3.10', '3.11', 'ctypes', '3.7']
title = 'variadic function call broken on armhf when passing a float argument'
updated_at = <Date 2021-07-23.09:26:19.255>
user = 'https://github.com/ndessart'

bugs.python.org fields:

activity = <Date 2021-07-23.09:26:19.255>
actor = 'Nicolas Dessart'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['ctypes']
creation = <Date 2020-02-14.10:03:28.170>
creator = 'Nicolas Dessart'
dependencies = []
files = ['48896']
hgrepos = []
issue_num = 39632
keywords = ['patch']
message_count = 4.0
messages = ['361992', '362307', '398026', '398040']
nosy_count = 2.0
nosy_names = ['FFY00', 'Nicolas Dessart']
pr_nums = ['18560']
priority = 'normal'
resolution = None
stage = 'patch review'
status = 'open'
superseder = None
type = None
url = 'https://bugs.python.org/issue39632'
versions = ['Python 3.7', 'Python 3.8', 'Python 3.9', 'Python 3.10', 'Python 3.11']